1. Field of the Invention
The present invention relates to a dry-disc type clutch, and more particularly to a clutch of the type which includes a fly wheel having an annular engaging surface and secured on a drive shaft, a clutch plate axially slidably supported on a driven shaft which is positioned in coaxial relationship to the drive shaft, annular friction facings secured to opposite surfaces of the clutch plate, and an annular pressure plate adapted to urge the friction facings of the clutch plate against the engaging surface of the fly wheel.
2. Description of the Prior Art
A clutch of the type described is generally positioned intermediate the crank shaft of an engine and the input shaft of a transmission. A fly wheel in the clutch is secured on an engine crank shaft i.e., a drive shaft for the clutch, and is configured with an annular engaging surface. Provided in engageable relationship to the annular engaging surface of the fly wheel is one of a pair of annular friction facings secured to a clutch plate having a hub which is slidingly fitted in splines of an input shaft for the transmission, i.e., the driven shaft of the clutch. One of the friction facings of the clutch plate is urged by means of an annular pressure plate against the engaging surface of the fly wheel, whereby a torque from the engine is transmitted through the medium of the fly wheel and clutch plate to the input shaft of the transmission.
However, clutches of the type described suffer from disadvantages in that, even if the clutch is brought into a disengaged position, the friction facings of the clutch plate tend to maintain contact with the engaging surface of the fly wheel, so that torque is transmitted through the crank shaft of the engine to the input shaft of the transmission, resulting in failure in changing over the speeds by the transmission.
It is, accordingly, a principal object of the present invention to provide a dry-disc type clutch which features characteristics of enhanced separation action of one of the friction facings of a clutch plate from an engaging surface of a fly wheel as a result of hydrodynamic forces produced by air streams generated in the clutch assembly.
It is another object of the present invention to provide a dry-disc type clutch which provides discharge passages for powder produced due to wear or attrition of the friction facings of the clutch.